It was the culmination of a six-month investigation, under the Protection of
Children Act, led by officers from Hertfordshire Constabulary and
Greater Manchester Police.

Detective Inspector Terry Jones, head of Greater Manchester Police's abusive
images unit, said of the people they were targeting: "We can detect them and
recover images they have accessed - but we are really doing it to explore their
lives and see if they are doing it to real kids."

"We will not be leaving those premises
until we are satisfied those children are safe," said Detective Inspector Keith Tilley, head of Hertfordshire Constabulary's child
protection and investigation unit.

Police said they believed many of those involved in swapping images may also be directly responsible for child abuse.

Detectives were able to make use of specialist equipment to trace computers being used by people entering the chat rooms anonymously.

The maximum sentence for downloading child porn photographs is 10 years in
prison.

Some business addresses were among the 75 searched by police in Operation Magenta.

Officers were making inquiries to establish who was using particular terminals at certain times.